Good info Ben and thank you for it! A word of caution however. Filing the outer face of the circumference of the bit can reduce its over all diameter. Your 3/4" bit can then become a 95/128" bit. For some applications, that may not be an issue but for many others, it is. This is even more important with auger bits where the discrepancy in diameter can cause the flutes to jam in the hole. Cheers and keep up the good work!

Although I agree with cleaning up the outside, I think grinding away material on the outside will ultimately change the diameter which isn't good if you want exact size holes.

Er, Acetone is one thing (the simplest Ketone) and has a definite chemical composition.Used for, amongst other things as nail polish remover! And for "gluing " and dissolving certain plastic guitar bindings. Naptha, actually, can mean a whole bunch of differing distillates from crude oil. Depending on the desired usage. But what is often referred to as naptha is good old lighter fluid... The two are definitely not the same.

Acetone is called Acetone in the U.S. Naptha is lighter fluid. ;)

Great tips Ben! You can use the electric bath method (forgot the name) to remove dirt and oxidation from anything metal really, so you don't have to remove material from the outer diameter. However, I would clean that part by placing the bit in the drill press, turning it on and holding a file against it. It will stay round like that. Also, to check whether all the cutting edges are on the same height, you can use fret rockers, or basically any thin straight piece and see if it rocks or if the center part is lower. You said that it doen't have to be mega sharp, but I check my tools if light can reflect on the edge, if it reflects light it's getting dull. However, the sharper the metal, the easier it will start to become dull (weaker). Cheers for this mini-torial!

Naptha is lighter fluid. Acetone can be bought as Acetone in pretty much any painting or automotive supply store. Boats and RV shops as well.

Thanks for a really useful answer to my question Ben. Guess what I'll be doing this evening !

No acetone is still called acetone in the USA and Naphtha is a different solvent all together.

Must bookmark this, as I bought exactly one Famag forstner bit, which I haven't even used yet. So will hopefully not have to come back to this for quite a while!

Very good Ben, I usually sharpen all my bladed tools but forsner bits I dont use much so when mine do get dull I throw them out & buy a new one. Thank you again

Eze-lap diamond paddles are perfect for this

Naphtha and Acetone here in the States r not the same thing. They may share some use applications but they r chemically very different.

I think polishing the outside edge of a circle with a flat faced tool is a terrible idea. You're almost guaranteed to put flat spots into it (and as Make Brooklynn says below, change the overall geometry). Some Autosol and a rag should do just fine after cleaning with acetone. The faces don't cut anything - only the leading edges of faces and the 2 center portions do.

I was always told you should not sharpen the outside of a forstner bit because it changed the radius of the bit.

Naptha is not acetone (propanone), diamond credit cards are the best thing for sharpening scissors.

I would never try to sharpen or shape the outside circular edges, hone the inside edges carfully with a small rounded stone or felt with polishing compound.

Naptha is also called Shellite in UK and Australia

@4:13 Capt Eddie says Don't touch this , or @9:18 , maybe 1000g wet n dry just to clean off any gunge ,

Cool how to, thanks

Could you use alcohol as a lubricant

You know I've always shied away from Forstner bits but I might bag a few second hand and have a go.... if anyone knows a good place to purchase let me know please!

no more sending em out for sharpening

60 Micron is about 250-260 grit. Here's a chart :) www.gessweincanada.com/category-s/11328.htm

You seem very wrapped up I hope you are warm enough